@article {
author = {Wu, P. Y. and Gau, H.-L.},
title = {Upper and lower bounds for numerical radii of block shifts},
journal = {Bulletin of the Iranian Mathematical Society},
volume = {41},
number = {Issue 7 (Special Issue)},
pages = {15-27},
year = {2015},
publisher = {Iranian Mathematical Society (IMS)},
issn = {1017-060X},
eissn = {1735-8515},
doi = {},
abstract = {For an n-by-n complex matrix A in a block form with the (possibly) nonzero blocks only on the diagonal above the main one, we consider two other matrices whose nonzero entries are along the diagonal above the main one and consist of the norms or minimum moduli of the diagonal blocks of A. In this paper, we obtain two inequalities relating the numeical radii of these matrices and also determine when either of them becomes an equality.},
keywords = {Numerical radius,block shift,minimum modulus},
url = {http://bims.iranjournals.ir/article_719.html},
eprint = {http://bims.iranjournals.ir/article_719_7b89cecc3c9d266bd2d8a5e08a8dc1cb.pdf}
}